Speculations on the Nenoksa Explosion[1] is interesting. I'm not qualified to judge its accuracy.
The author's opinion is that it had to have been U-235:
"When you are concerned about weight, as a cruise missile designer must be, the places to look in these designs would be the moderator and reflector for the reactor. Highly (above 90%) enriched uranium is the only possible fuel; plutonium is too hard to handle, and lesser enrichments add too much weight. The moderators in the Tory and Rover reactors also served as structural elements."
Speculations on the Nenoksa Explosion[1] is interesting. I'm not qualified to judge its accuracy.
The author's opinion is that it had to have been U-235:
"When you are concerned about weight, as a cruise missile designer must be, the places to look in these designs would be the moderator and reflector for the reactor. Highly (above 90%) enriched uranium is the only possible fuel; plutonium is too hard to handle, and lesser enrichments add too much weight. The moderators in the Tory and Rover reactors also served as structural elements."
[1] https://nucleardiner.wordpress.com/2019/08/11/speculations-o...